The invention relates to a heat exchanger block, having a row of heat exchanger walls which are arranged at a distance from one another and define intervening heat-exchange medium flow chambers for at least a first heat-exchange medium and a second heat-exchange medium which is to be brought into heat-exchanging contact therewith. The heat exchanger block has a plurality of thermally conductive rods which extend, at a distance from one another in a two-dimensional arrangement, all the way through the row of heat exchanger walls and the intervening heat-exchange medium flow chambers.
Various heat exchanger blocks with a row of heat exchanger walls which are at a distance from one another and define intervening heat-exchange medium flow chambers are known and can be used for heat exchanger units of automotive air-conditioning systems, for example, as evaporators or condensers or gas coolers. For example, EP 0 219 974 B1 describes an air-cooled condenser with its heat exchanger block formed by flat tubes, which are arranged at a distance from one another in the direction of the row, and intervening corrugated fins. At their ends, the flat tubes open into associated manifolds, in order for a coolant or refrigerant of a cooling or air-conditioning system to be fed into the flat tubes in parallel and discharged again therefrom. To impart the necessary strength to such flat tube/fin blocks, the flat tubes are typically brazed to the fins and at their ends are fitted into slots in the manifolds, to which they are then brazed. Air is passed through the flat tube interspaces, in order to bring this air into heat-exchanging contact with the coolant or refrigerant. The fins allow the active heat-transfer surface area to be enlarged.
Swiss Patent CH 641 893 A5 discloses a heat exchanger block which is cast in a single piece using a precision casting technique and comprises a cube-sided housing, which is only open on two opposite sides, a plurality of parallel transverse walls extending, as heat exchanger walls, between two opposite side walls, these heat exchanger walls dividing the housing cavity into a plurality of heat-exchange medium flow chambers for at least two heat-exchange media which are to be brought into heat-exchanging contact with one another. In each case a plurality of thermally conductive pins, which are at a distance from one another in a two-dimensional arrangement, extend from one transverse wall to a respectively adjacent transverse wall, only through the associated heat-exchange medium flow chamber. On account of this structure, the production of this heat exchanger block requires a relatively complex casting process using wax leaves which have to be melted out and cores which have to be dissolved after the introduction of the casting metal.
U.S. Pat. No. 5,655,600 describes a heat exchanger block of the type described in the introduction which is in plate form and in which the heat exchanger walls are formed by plates that are stacked on top of, but at a distance from, one another. Between the outer plates, thermally conductive rods extend through the row of plates with the intervening heat-exchange medium flow chambers, at a distance from one another in a two-dimensional arrangement. The plates and rods consist of a fiber-reinforced composite material, as an alternative to aluminum material which is customarily used. Preferably, a composite material having a higher thermal conductivity than that of aluminum is selected.
It is one object of the invention to provide a heat exchanger block of the type described in the introduction which can be produced with relatively little outlay yet with a high compressive strength and a high heat-exchange capacity.
It is also an object of the invention to provide an improved automotive air-conditioning system.
In accomplishing these and other objects, there has been provided in accordance with one aspect of the present invention a heat exchanger block, comprising: a first row of heat exchanger tubes comprising flat-tube sections including a pair of flat wall sections, the flat-tubes being arranged at a distance from one another in the direction of the row, wherein the interiors of the flat-tubes form first heat-exchange medium flow chambers for at least a first heat-exchange medium and the interspaces between the flat-tubes form second heat-exchange medium flow chambers for at least a second heat-exchange medium which is to be brought into heat-exchanging contact with said first heat-exchange medium; and a plurality of thermally conductive rods, extending completely through the flat wall sections of each tube of the first row of heat exchanger tubes, so as to also extend through the intervening second heat-exchange medium flow chambers, the rods extending at a distance from one another in a two-dimensional arrangement.
In accordance with another aspect of the present invention there has been provided an automotive air-conditioning system, comprising a compressor and a heat exchanger, wherein the heat exchanger has the design described above.
Further objects, features and advantages of the present invention will become apparent from the detailed description of preferred embodiments that follows, when considered together with the accompanying figures of drawing.